1. Field of the Invention
The invention relates to a microscope having a proximity sensor and a control circuit for automatically switching electrical microscope functions.
2. Description of Related Art
Modern microscopes are distinguished, inter alia, by the fact that the various microscope functions are designed in such a way that they can be controlled electrically and/or by electric motor. For example, known electrically operating switching and adjusting functions are autofocusing devices, motor-driven adjustments of the specimen stage, electrically switchable shutters, filters or phase-retarding rings etc. A microscope in which these functions are realized is described, for example, in DE 42 31 379 A1.
In this microscope, the operating elements for the switching functions are grouped together in an ergonomic way on a control console and have to be manually selected by the observer. This has proved successful in practice. However, due to the large number of electrically controllable microscope functions, the area around the microscope, and consequently also the specimen to be observed, is exposed to heat. In particular when using lighting devices with very high lamp outputs, such as for example gas-discharge lamps, the specimen may be damaged by the heat to which it is exposed. Particularly sensitive specimens are, for example, living cells or else specimens in fluorescence microscopy, which may be destroyed by high luminous intensities.
The observer is in these cases obliged to deactivate or switch the switchable function manually by means of the control console. It has been found in practice that, for many applications, this procedure is always inconvenient if, for example, the microscope function is not required for a short time.
In the case of photographic cameras, it is known to arrange on or in the viewfinder a sensor which activates or deactivates the entire main circuit of the camera according to whether or not the photographer is looking into the viewfinder. In the case of cameras, this is only with the intention of saving the battery.
In the case of microscopes it is also the case that the main circuit must not be interrupted, since this would necessitate complete re-setting of the microscope when the functions were activated once again. In addition, the lifetime of lamps is reduced considerably by frequent switching on and off.
WO 96/13743 A1 discloses a microscope with a sensor and a control device, in which the microscope functions can be controlled contactlessly by the position of the observer""s pupil. A device for detecting the position of the pupil is equipped with a switching element, which interrupts the measuring routine as soon as the device for detecting the position of the pupil cannot perceive a pupil.
Furthermore, DE 44 46 185 A1 discloses a laser scanning microscope with a UV laser and with an optical fiber, in which the damage caused by UV light is reduced by providing between the laser and the optical fiber a scanning shutter, which exposes the optical fiber only during scanning.
It is therefore an object of the present invention to develop a known microscope with simplest possible means in such a way that, independently of the manual operation by a person, the electrical and/or electric-motor-driven microscope functions can also be performed fully automatically, and at the same time damage to sensitive specimens or impairment of the image quality is reduced.
This object is achieved according to the invention by the features specified herein. According to an embodiment of the present invention, a microscope includes a viewing tube for the visual examination of a specimen and an illumination device for illuminating the specimen. The microscope comprises a control circuit housed in the microscope for activating electrical microscope functions and a proximity sensor connected to the control circuit and fitted on the microscope for responding to the absence of an observer viewing the specimen through the viewing tube. The control circuit includes an adjustable time-delay logic element located in the control circuit for delaying switches of the microscope functions such that the microscope functions are switched after the observer is absent for a predetermined time period. Further advantageous developments of the invention are also described.
The arrangement of a proximity sensor on or in the eyepiece and its connection to the control circuit make it possible for microscope functions to be controlled fully automatically. These functions are initiated whenever the user looks into the eyepiece on the tube, or if said user does not look in. This fully automatic control has proved successful in particular in fluorescence microscopy for swiveling an occulting shutter in and out of the illuminating beam. This avoids a gradual bleaching of the specimen (fading effect) being caused by unnecessary illumination.
The obscuring of the illuminating light by an occulting shutter or by regulating the lamp voltage is of course also advisable if living tissue or cells are to be observed and/or worked on using the microscope.
The proximity sensor is advantageously also used in the case of microphotographic exposures. In this case, to avoid the incidence of extraneous light through the eyepiece, an occulting shutter is swiveled into the observing beam. Of course, it is also possible to activate a beam-splitting mirror by means of the proximity sensor and the control circuit, so that all of the light coming from the specimen can be used for the photographic exposure.
Thus, according to an embodiment of the present invention, a microscope includes an observation beam path, an observation tube for an observation of a specimen, a control circuit for activating electrical microscope functions, and an illumination system for illuminating the specimen. The microscope further includes an eyepiece coupled to the observation tube for observing the specimen, a camera, a movable mirror positionable in the observation beam path, and a proximity sensor coupled to the observation tube and the control circuit. Upon the approach of an observer to the eyepiece, the proximity sensor emits a signal. A position of the movable mirror corresponds to the signal of the proximity sensor and the observation beam path propagates to one of the observation tube and the camera based on the position of the movable mirror.
A commercially available proximity sensor, forming a separate structural unit, may be used on the tube of the microscope. The proximity sensor may in this case be designed as a light sensor, such as for example as a reflection barrier, a forked light barrier, a passive infrared detector or an ultrasonic detector. A contact-sensitive switch may also be used as the proximity sensor.
According to another embodiment, a microscope includes an observation beam path, an observation tube for an observation of a specimen, a control circuit for activating electrical microscope functions, and an illumination system for illuminating the specimen. The microscope further includes an eyepiece coupled to the observation tube for observing the specimen, a camera coupled to a photo-tube, a movable mirror positionable in the observation beam path, and a proximity sensor coupled to the observation tube. Upon the approach of an observer to the eyepiece, the proximity sensor emits a signal. The control circuit is coupled to the movable mirror and changes a position of the movable mirror corresponding to the signal of the proximity sensor. The observation beam path propagates to one of the observation tube and the camera based on the position of the movable mirror. In addition, the microscope can include an actuator coupled to the moveable mirror and the control circuit to place the movable mirror in a first position which allows propagation of the observation beam path into the eyepiece and a second position which allows propagation of the observation beam path into the photo-tube. Preferably, the actuator is one of a motor and an electromagnet.
Also, according to this embodiment, the microscope can include an adjustable time-delay logic element coupled to the control circuit, responsive to the presence and absence of the signal from the proximity sensor, for delaying switches of the microscope functions such that the microscope functions are switched after the observer is absent for a first continuously adjustable time period to protect the specimen and to prevent frequent switching of the illumination device when the observer is momentarily absent from an observing position. Further, the control circuit can provide a trigger for a first change of the position of the movable mirror upon the presence of a continuous signal from the proximity sensor for a second continuously adjustable time period of about 1 second to about 1 minute.
Other advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing.